Date Time Picker Control Problem

And what is your problem?
I can't work it out from your question - do you want to select a null the second time? Or it is doing it for you?
Please, show some relevant code fragment if you have behaviour you don't expect!
Use the "Improve question" widget to edit your question and provide better information.

Please don't think we can read minds or do astral projections to see your monitor. If you need help, the least you could do is to add some relevant code to your question or to explain your problem in such a way, that the users of CP can understand it. Otherwise, nobody will be able to help you.
what have you tried?[^]